If the Seahawks signed him this year, how would he factor into compensatory picks (for next year, obviously)? Since his Option was declined, is he considered cut or is he considered simply having his contract expired like a regular, qualifying free agent?

Players with an option not picked up (like Okung, Clady, and Beachum) are not considered cut. They are consider full unrestricted free agents and do indeed count towards the compensatory picks next year. That's why they aren't making the rounds now with teams and they have to wait to visit and sign with someone until the official free agency period. Players that were actually cut are able to visit teams and sign a deal immediately (like Earl Mitchell that the 49ers signed last week).

Yes, he counts against the formula. But since we aren't losing any notable free agents (none that should get a decent-sized contract), we aren't going to get any comp picks next year anyways. So we might as well sign whoever we want.